Bioptics bar code reader

ABSTRACT

A bioptics bar code reader has first and second windows disposed at an angle to each other, a first imager for the first window and a second imager for the second window and first and second optics for directing light from a bar code in a reading area between the windows to the first and second imagers. The two imagers each obtain an image of the bar code in the reading area.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to the reading of dataforms, such as bar codes, by the use of imagers in slot or presentation mode scanners.

[0002] The reading of bar codes by imagers is known, and imagers, such as charge coupled detector (CCD) arrays or CMOS sensors, have been disclosed in U.S. Pat. No. 5,319,181, the disclosure of which is incorporated herein by reference. Such imagers are also referred to as cameras, sensors and the like.

[0003] It is proposed that the use of two images of the same bar code from two different views will aid in the speed and reliability of decoding bar codes which have been captured as an image in an imager.

[0004] Moreover, although two-dimensional bar codes have been increasing in use, there are currently no presentation or slot scanners available in the market today that can read a two-dimensional bar code from two sides of a package.

SUMMARY OF THE INVENTION

[0005] The main object of the present invention is to improve the slot scanners that are presently available.

[0006] Another object of the present invention is to provide a bioptics reader which reads bar codes using area sensor cameras which can process the signals in sequence or in parallel with the capability of taking and storing one-dimensional pictures and increasing the reliability of the system by eliminating any moving parts.

[0007] In accordance with the present invention, this object is achieved by two or more area imagers positioned within the bioptics scanner or reader in such a manner that their fields of view cover a three-dimensional space where a bar code can be presented or an identification document might be seen by the imagers. Liquid crystal displays or other conventional displays can also be used by being mounted in front of an operator so that the operator will be able to see the views of the cameras in real time. In addition, illumination lights can be mounted inside of the slot scanner, so that the numerical apertures of the camera or imager can be optimized for the deepest depth of focus.

[0008] Another object of the present invention is to provide a bioptics scanner or reader for a slot or presentation mode which is capable of reading one and two-dimensional bar codes.

[0009] This object is achieved in accordance with the present invention by the use of two transparent scanning surfaces or windows which are at an angle to one another, two fixed mirrors and one moving mirror for use with a single image sensor. The image sensor is preferably an interlaced image sensor, however, any image sensor can be used wherein one can expose the photodetector at two separate times in one frame.

[0010] In accordance with the invention, the mirror is moved between positions and an even field of the image sensor is exposed obtaining the image of the side of the package facing the horizontal scanning surface. When the mirror is in a second position, the odd field of the image sensor is exposed resulting in an image of the package facing the vertical scanning surface. This results in one frame of a scanner having two views of the different sides of the package. Once the images are obtained, the bar code and the image can be located and decoded. To increase the speed of operation, one can either start decoding a particular odd or even field while the other is being read out or one can process the two at once. The current transport speed of the package can be 50 inches per second, however, higher speeds can be achieved by optimizing the hardware and software of the system.

[0011] These and other features of the present invention will be disclosed in more detail from the following detailed description taken with the attached drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a partial sectional view of a bioptics slot or presentation mode scanner in accordance with the present invention;

[0013]FIG. 2 is a schematic of the circuitry of the scanner of FIG. 1;

[0014]FIG. 3 is a schematic of an alternative embodiment of a bioptics scanner according to the present invention; and

[0015]FIG. 4 is a timing diagram showing the sequence of events of operation for the scanner of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Referring now to FIGS. 1 and 2, a first embodiment of the bioptics scanner according to the present invention is disclosed.

[0017] In a slot and/or presentation mode scanner, there are two windows 1 and 2 which are at an angle to each other. Although the windows 1 and 2 are at a 90° angle in FIG. 1, other angles can be used. In FIG. 1, window 1 is a horizontal window and window 2 is a vertical window, however, other orientations can also be used within the scope of the invention.

[0018] Behind the windows 1 and 2 are two dimensional array cameras 3 and 4 respectively which are positioned with regard to mirrors 5 and 6 so that their fields of view cover a three-dimensional space where a bar code B can be presented on a three-dimensional object or an identification document, such as a coupon, might be presented. Mirrors 5 and 6 are stationary mirrors which reflect light from the bar code B onto imagers 3 and 4 respectively.

[0019] In order to improve the depth of focus of the imagers 3 and 4, illumination lights 7 and 8 are disclosed behind the windows and optionally utilized light condensers 9 and 10 respectively. Mirrors 5 and 6 are light dividing mirrors, so that light from the light sources 7 and 8 can pass therethrough and light returning from the bar code can be reflected to the cameras or imagers 3 and 4. By use of the illumination lights, the cameras can have their numerical apertures optimized to obtain the maximum depth of focus.

[0020] In a preferred embodiment of the present invention, LCD or other conventional displays 11 and 12 are associated with the imagers 3 and 4, so that the operator can see the views of the cameras or imagers 3 and 4 respectively.

[0021] The outputs of the imagers 3 and 4 are also connected to a decoder 13 which has the capability of processing the signals from the two imagers either sequentially or in parallel. The decoder 13 can perform the decoding in parallel by having two duplicate circuits, each servicing one imager.

[0022]FIG. 3 illustrates another embodiment of the present invention, wherein two windows 21 and 22 have two fixed mirrors 23 and 24 associated therewith and a single imager 26. A moveable mirror 25 is disposed between the mirrors 23 and 24 and is moveable between two positions marked A and B in FIG. 3. The output of the imager 26 is fed to a decoder 27.

[0023] With reference to FIG. 4, the operation of the embodiment of FIG. 3 will now be explained. The imager 26 is preferably an interlaced image sensor which has even fields, i.e., lines 2, 4, 6, 8, 10 . . . , and odd fields, i.e., lines 1, 3, 5, 7, 9 . . . When the mirror is in position A, the even field of the imager is exposed and an image of the side of the package facing the horizontal scanning window 21 is obtained. When the mirror is in the position B, the odd field of the imager 26 is exposed resulting in an image of the packaging facing the vertical scanning window 22. This results in one frame of the scanner having two views of the different sides of the package.

[0024] Once the images are obtained, the bar code and the image can be located and decoded by decoder 27. To increase the speed of operation, one can start decoding a particular (odd or even) field while the other is being read out, as is shown in FIG. 4. The transport speed of the package for the present invention is 50 inches per second, however, higher speeds can be achieved by optimizing the hardware and software.

[0025] It is understood that the embodiments described hereinabove are merely illustrative and are not intended to limit the scope of the invention. It is realized that various changes, alterations, rearrangements and modifications can be made by those skilled in the art without substantially departing from the spirit and scope of the present invention. 

What is claimed is:
 1. A bioptics bar code reader comprising: first and second windows disposed at an angle to each other; a first imager for the first window and a second imager for the second window; and first and second optics for directing light from a bar code in a reading area between the windows to the first and second imagers; whereby the two imagers each obtain an image of the bar code in the reading area.
 2. The reader according to claim 1 , further comprising first and second light sources behind the first and second windows and wherein the first and second imagers have numerical apertures configured for a maximum depth of focus.
 3. The reader according to claim 1 , further comprising first and second light sources behind the first and second windows and wherein the first and second optics comprise a first light dividing mirror for permitting light from the first light source to pass therethrough and through the first window onto the bar code in a reading area and for reflecting light from the bar code to the first imager and a second light dividing mirror for permitting light from the second light source to pass therethrough and through the first window onto the bar code in the reading area and for reflecting light from the bar code to the second imager.
 4. The reader according to claim 3 , further comprising a first light condenser between the first light source and the first mirror and a second light condenser between the second light source and the second mirror.
 5. The reader according to claim 1 , wherein the first and second imagers comprise charge coupled diode arrays.
 6. The reader according to claim 1 , further comprising at least one display receptive of images from the imagers for displaying the images seen by the imagers to an operator.
 7. The reader according to claim 3 , wherein the mirrors are stationary.
 8. The scanner according to claim 1 , further comprising at least one decoder receptive of the images from the first and second imagers for decoding the bar code imaged thereby.
 9. The scanner according to claim 8 , wherein the decoder decodes the bar code from the imagers sequentially.
 10. The scanner according to claim 8 , comprising two decoders for decoding the bar codes from the two imagers in parallel.
 11. A bioptics bar code reader comprising: first and second windows at an angle to each other; a first folding mirror behind the first window and a second folding mirror behind the second window; an imager; and a movable mirror for reflecting light from a bar code in a reading area between the windows alternatively from the first window and first mirror and the second mirror and second window wherein the imager has first and second interlaced fields and wherein the imager images the image from the first window in the first field and the image from the second window in the second field.
 12. The reader according to claim 11 , wherein the imager comprises a charge coupled detector array or a complimentary metal oxide semiconductor (CMOS) imager.
 13. The reader according to claim 11 , further comprising a decoder for decoding the bar code imaged by the imager.
 14. The reader according to claim 13 , wherein the decoder decodes the image from the first window and then the image from the second window. 